Novel Co–Ni–graphene composite electrodes for hydrogen production

Abstract

A novel, highly efficient composite electrode containing earth-abundant elements (Co–Ni) and graphene has been developed for the electrocatalytic hydrogen evolution reaction in an alkaline medium.

Polymorph nickel titanate nanofibers as bifunctional electrocatalysts towards hydrogen and oxygen evolution reactions

“…Both the survey spectra Figure S4a and 6a confirms the presence of C, O, Ti, and Ni elements 13,40,41 distributed non-homogeneously over the NTO nanofibers (ratio of intensity of respective elements is not equal to one). 11 The deconvoluted high-resolution spectra of Ni 2p, Ti 2p, and O 1s ( Figure S4b-d) confirms the formation of ilmenite NTO, which is in good accordance with literature. 13,40,42 It has to be noted that the deconvoluted peaks in each individual graph ( Figure 6 and S4) are representative and similar deconvoluted peaks exists in all the three high-resolution spectra of corresponding graph.…”

“…The protons from the electrolyte are adsorbed on the active sites of the electrocatalyst surface (cathode) through HER and receive electrons to form chemisorbed hydrogen atoms, which later disengage as hydrogen gas. 11,49,50 In this regard, CV analysis is a well-established technique to comprehend the thermodynamics of redox reactions and kinetics of adsorption process. Besides, the CP analysis is a basis for evaluating the material stability, where a definite controlled current is applied between electrodes (three electrode system) as the redox reactions occur at the active sites of the working electrode.…”

“…8,9 Besides, multiple adsorption/desorption processes that occur during electrolysis can be synchronized by using heterostructures of Ni-based materials, thereby forming more active catalytic sites. Many Nibased heterostructures have been explored in literature for their applicability as electrocatalysts 6 as well as photocatalysts 7 , such as Ni-W alloy 10 , Co-Ni-graphene composite 11 , Ni(OH)2/Ni 12 , NiTiO3/Ni 13 , NiO/TiO2 14 . However, these materials as electrocatalysts have some drawbacks such as high overpotential or are based on metallic Ni.…”

Seawater splitting for hydrogen evolution by robust electrocatalysts from secondary M (M = Cr, Fe, Co, Ni, Mo) incorporated Pt

“…The HER at electrode/seawater interface is considered as a multi-step process. 30,31 The rst step is Volmer or discharge reaction: an electron transfers to the catalytic electrode and couples with a proton, which is adsorbed on the empty active sites of the electrode to obtain absorbed hydrogen atom. In acidic electrolytes, the proton source is contributed to hydronium cation (H 3 O + ), it is H 2 O molecule in alkaline solutions.…”

Nickel nanoparticles coated on the exfoliated graphene layer as an efficient and stable catalyst for oxygen reduction and hydrogen evolution in alkaline media

“…To date, carbonaceous materials in presence or absence transition-metal nanoparticles have been investigated as novel electro-catalysts for ORR [22,23,35], oxygen evolution reaction (OER) [27,36], methanol oxidation reaction [37], photocatalyst [38,39] HER [30,40,41].…”